Relationship advice

My boyfriend and I have been dating for just under a year, when we first met he was a completely different person, be at the pub everyday, gamble a lot (at the pokies and on sportsbet) I fell in love with him but he was a different person. Since we were together he’s changed for the better (not that I asked him too)

He never gambles, doesn’t drink and has just grown up a lot (he’s 24). But lately his friend group have sort of fallen apart. They’ve been going out without him so he messaged them and asked what was going on. Al the guys in the group are fine with him but the two girls aren’t. They said that he’s just not a person who they want to be around, he’s immature and just needs to grow up but they don’t spend time with him to be able to see that he has grown up. It’s really hitting him hard because his friends are his family. They’ve all been friends since they were kids. I just don’t know what to tell him or how to help him.